The invention relates to novel polyaromatic cyanates, a novel process for preparing the polyaromatic cyanates and to novel polytriazines prepared from the polyaromatic cyanates.
It is known from German patent Specification No. 1,190,184 that high molecular weight polytriazines can be obtained by polymerizing difunctional or polyfunctional aromatic cyanates at elevated temperature, optionally in the presence of polymerization promoters. The polymers are characterized for example by their remarkable stability at elevated temperatures and they are duroplastic in character after tempering for a sufficiently long period. The resistance of the polytriazines to acids and various solvents may also be emphasized.
In addition, it was found by V. V. Korchak et al. (cf. Vysokomolekulyarnye Soedineniya 1974, number 1, pages 15 to 21) that the thermal and thermo-oxidative destruction of polytriazines based on aromatic cyanates is greatly influenced by moisture.
Finally, it is known from German patent No. 1,720,740 that polyfunctional aromatic cyanates can be combined with powder-form and/or fibrous fillers or reinforcing materials and subjected either to a preliminary or subsequent heat treatment at about 50.degree. C. to 150.degree. C., the resulting molding composition molded and hardened at temperatures in the range from about 150.degree. C. to 250.degree. C. In many cases the resulting moldings also show inadequate thermal stability after storage in a moist, tropical atmosphere.
Polyaromatic cyanates which prepare polytriazines which are hydrolytically stable are needed. Polyaromatic cyanates which are useful in preparing polyaromatic triazines which are thermally stable are further needed.